Improve debounce handling

[utopiafallen]

KeyStateCoolDown is reset on every key down event instead of only when a key press event would trigger. This fixes my key chatter issue where I think my keys were oscillating rapidly between up/down states over a period of time that could overlap with the cooldown mechanism in such a way as to trigger multiple key presses in a short period of time.

By resetting the cooldown on every key down state, oscillations are suppressed because the key up and refresh delays to only start elapsing once the key has stabilized in the up state.

[nitsujri]

I'm facing the same problem even with v2.8 flashed in.

How did this compare to just increasing KeyUpDelay / builder_keyup_delay? It seems like that's the original mechanism designed to ignore oscillations on the contacts.

[utopiafallen]

Fiddling with the KeyUpDelay was kind of like playing whack-a-mole for me where I was trying to find a value that retained responsive key-presses while suppressing chatter on problematic keys. That got tedious pretty quickly and would need periodic adjustments as new keys started chattering or old keys got worse.

This patch lets you keep a short KeyUpDelay while effectively letting problematic keys auto-scale its KeyUpDelay based on how "chatty" it is. Basically, the new debounce algorithm in 2.8 was very close to being right and this was the missing change for me. I have had no issues with key chatter since I made the change. You can tell from the diff that the change is pretty trivial to just make yourself and try it out locally.

[nitsujri]

Great, I'll give it a go first instead of trying the KeyUpDelay wack-a-mole.